Method for curing a RMA crosslinkable resin coating, RMA crosslinkable compositions and resins for use therein

ABSTRACT

A method for curing of a coating of RMA crosslinkable compositions, to RMA crosslinkable compositions and A method for curing of a coating of an RMA crosslinkable composition involving two or more different curing mechanisms, wherein the two or more different curing mechanisms involve a) RMA crosslinking in combination with a second crosslinking reaction between hydroxy groups on the RMA crosslinkable components with polyisocyanates or siloxanes; or b) RMA crosslinking in combination with a second crosslinking reaction with polyamines, with crosslinkable components comprising component B and/or with epoxy groups on the RMA crosslinkable components; or c) RMA crosslinking in combination with a second crosslinking reaction based on auto-oxidative drying of unsaturated groups on the RMA crosslinkable components; or d) RMA crosslinking in combination with a second radical crosslinking reaction of reactive components B on the RMA crosslinkable components; or f) combinations thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a 371 of PCT application number PCT/EP2016/058590filed on Apr. 18, 2016, which claims priority from EP application number15169719.0 filed on May 28, 2015, and U.S. Provisional Application No.62/148,981 filed on Apr. 17, 2015. All applications are herebyincorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

The invention relates to a method for dual curing a RMA crosslinkableresin coating, to RMA crosslinkable compositions and to resins for usein the method. The RMA coating method and composition can be used fordirect to concrete application, to wood coatings and coatings that areeasy-to-clean, anti-graffiti and sanitisable coatings

A variety of different types of resins are known in the prior art thatcan form the binder of a coating composition. The dominant technologiesthat are currently being used are epoxy-amine and polyol-polyisocyanate.Although these resin systems have their merits, they also pose someimportant limitations as the use chemicals that have toxicologicalprofiles that are questionable (bisphenol A/F in epoxy resins, aminecuring agents, monomeric diisocyanate in polyisocyanate hardeners). Afurther disadvantage of polyol-polyisocyanate floor coating systems isthat, during the application, they are moisture sensitive. Epoxy-aminefloor coating systems have a further disadvantage that they cannot becured at relatively low temperatures below 15 or 10° C. which may oftenoccur in outdoor applications. Consequently, there is a desire for acoating composition that has a more favorable toxicological profile, canbe cured also at low temperatures and also in moist conditions.

Another important parameter for coating applications is the workingtime. This is the time following mixing of the basic ingredients duringwhich the coating can be applied and finished without detrimental effecton its properties such as adhesion, compaction and surface finish. Thisproperty is very much linked to the consistency of the resin.Epoxy-amine and polyol-polyisocyanate systems will start reactingchemically already in the liquid state directly after mixing. Thisimplies that the viscosity of the mixed liquid resin flooring will startto increase, reducing the fluidity and the ability of the resin flooringto flow and level. Coating compositions having a good working time areknown. For example alkyd resins have a good working time. However buttake a rather long time to cure and fully develop the mechanicalproperties required for the end use (service time). This limits the useto relatively thin layers which harden faster than thick layers and alsoleaves a desire for better mechanical properties and chemical resistanceof the resulting cured coating. Therefore there is still a desire forcoating compositions with a more favorable balance of the counteractiverequirements of working time and time to service.

Another desire is that the coating compositions have a low volatileorganic content for safety, environmental and health reasons, inparticular when applied in poorly ventilated circumstances, inparticular indoor. This requirement is contra-active to achieving ahigher fluidity and improved working time through the use of a volatileorganic solvent. With volatile solvent herein is meant, unless otherwisedescribed, the organic compounds having a boiling point below 250° C.present in the composition ready for use.

Apart from the above requirements the coating preferably also has a verygood adhesion to the substrate and has a good water and chemicalresistance, a high resistance to impact and abrasion, an opticallyattractive surface, a low dirt pickup- and adhesion and be easy toclean.

BRIEF DESCRIPTION OF THE INVENTION

There is a desire for improved coating compositions that do not have oneor more of the above mentioned disadvantages of the prior art. Inparticular there is a desire for a resin for a method for curing RMAcoating compositions having a better balance of properties in view ofthe above described requirements.

According to the invention one or more of the above mentioned problemsare solved by a method for curing of a coating of a RMA crosslinkablecomposition involving two or more different curing mechanisms, said RMAcrosslinkable composition comprising at least one crosslinkablecomponent comprising reactive components A and B each comprising atleast 2 reactive groups wherein the at least 2 reactive groups ofcomponent A are acidic protons (C—H) in activated methylene or methinegroups (RMA donor group), and the at least 2 reactive groups ofcomponent B are activated unsaturated groups (C═C) (RMA acceptor group)which reactive groups react to achieve crosslinking by Real MichaelAddition (RMA) reaction in the presence of a base catalyst (C), saidmethod involving the steps of

-   -   a. Providing a RMA crosslinkable composition    -   b. Applying a layer of said RMA crosslinkable composition    -   c. Allowing curing of the layer by RMA crosslinking    -   d. Before during or after said RMA crosslinking applying a        second crosslinking reaction step,        wherein the two or more different curing mechanisms involve    -   a. RMA crosslinking in combination with a second crosslinking        reaction between hydroxy groups on the RMA crosslinkable        components with polyisocyanates or siloxanes or    -   b. RMA crosslinking in combination with a second crosslinking        reaction with polyamines, with crosslinkable components        comprising component B and/or with epoxy groups on the RMA        crosslinkable components    -   c. RMA crosslinking in combination with a second crosslinking        reaction based on auto-oxidative drying of unsaturated groups on        the RMA crosslinkable components or,    -   d. RMA crosslinking in combination with a second radical        crosslinking reaction of reactive components B on the RMA        crosslinkable components and/or optional other radical        crosslinkable polymer components, preferably by UV curing or by        thermal curing preferably with peroxy, or    -   e. Combinations thereof        wherein said second crosslinking reaction step is performed        before, during or after the RMA curing.

The inventors have found that the method has very favorable propertiesin coating applications. RMA crosslinkable compositions were found tohave very good properties for use in in highly demanding coatingapplications as for example in synthetic flooring and floor coatingapplications. Dual cure was found to increase overall conversion andwill enhance Tg, XLD, easy to clean properties, chemical and mechanicalresistance. Radiation curing in particular will enhance surface Tg,surface XLD, blocking resistance, EtC properties, chemical resistance.

In one embodiment of the method the RMA crosslinkable compositioncomprises a RMA crosslinkable resin containing one or more fattycomponents selected from the group of fatty acids, fatty alcohols, fattyamines, fatty thiols, preferably fatty acids or fatty alcohols, and atleast 2 reactive groups which are acidic protons (C—H) in activatedmethylene or methine groups wherein the activated C—H reactive groupsare in one or more reactive components A having a structure according toformula 1:

wherein R is hydrogen or an alkyl or aryl and Y and Y′ are identical ordifferent substituent groups, preferably alkyl, aralkyl or aryl (R*), oralkoxy (—OR*) or wherein the —C(═O)—Y and/or —C(═O)—Y′ is replaced by CNor aryl, preferably by no more than one phenyl, preferably anacetoacetate or a malonate, most preferably a malonate.

The RMA crosslinkable resins comprises fatty compounds, preferably fattyacids, having unsaturated groups, epoxy groups or hydroxy groups orcombinations thereof. Said fatty compounds, preferably fatty acidscomprise C8 to C18 chain with 20, 25, 30 or 40 to 99 wt %, preferably 60to 99 wt % of the fatty acids being unsaturated fatty acids forauto-oxidative crosslinking and wherein the RMA crosslinkablecomposition preferably also comprises a drier salt.

In another embodiment the RMA crosslinkable resin comprises fattycompounds, preferably fatty acids comprise a C8 to C18 chain withhydroxyl groups and/or comprise other hydroxyl groups on thecrosslinkable components and the RMA crosslinkable composition furthercomprises polyisocyanates or siloxanes for crosslinking with thehydroxyl groups.

In another embodiment the RMA crosslinkable resin comprises fattycompounds, preferably fatty acids comprising a C8 to C18 chain withepoxy groups and the RMA crosslinkable composition further comprisespolyamines.

In another embodiment the RMA crosslinkable composition comprises athermal or radiation radical initiator for thermal or radiation radicalcrosslinking and optionally also an excess of reactive components B overreactive components A in the RMA crosslinkable composition.

In another embodiment the RMA crosslinkable composition comprises aradical initiator and crosslinking, preferably UV crosslinking, is doneafter RMA curing to achieve further reaction of unreacted component B inparticular in the surface area of the coating.

In another embodiment the RMA crosslinkable composition comprises aradical initiator and crosslinking, preferably UV crosslinking, is donebefore RMA curing to increase the viscosity of the coating layer beforeRMA curing.

In another embodiment the RMA crosslinkable composition comprises morethan 60 wt %, preferably more than 70, 80 or 90 wt % radical curablecomponents, less than 40, preferably less than 30, 20 or 10 wt % of RMAcrosslinkable components comprising component A, the sum thereof being100 wt %, and a radical initiator and wherein crosslinking, preferablyUV crosslinking, is done after an initial RMA curing to increase theviscosity of the coating layer before UV curing.

In another embodiment the RMA crosslinkable composition compriseacrylate as well as methacrylate acceptors as components B (acceptors).

The invention also relates to a RMA crosslinkable composition and to RMAcrosslinkable resins as described herein.

Most preferred resins are RMA crosslinkable resins wherein the one ormore reactive components A are predominantly malonate and the RMAcrosslinkable resin has an hydroxy value OHV between 20-300, preferably20-200 or 50-150, more preferably 75-125, most preferably 80-115. It wasfound that these resins have good potlife, adhesion and dry timeproperties. Particular preferred RMA crosslinkable resins comprise areactive component A, preferably a malonate or acetoacetate, mostpreferably malonate, or comprising a reactive component B preferably anacryloyl, or both reactive components A or B is characterised by

-   -   a) Molecular weight Mw (weight average) is between 1000-20000,        preferably 2000-15000, more preferably 2500-10000    -   b) Hydroxy value OHV is between 20-300, preferably 20-200 or        50-150, more preferably 75-125, most preferably 80-115    -   c) Acid value AV is below 5, preferably below 3, 2 or even 1,    -   d) Equivalent weight EQW (per C—H/C═C group) is between 85-1000,        preferably 100-750, more preferably 125-500, 150-400 or even        175-300,    -   e) Functionality defined as number average number of C—H/C═C        groups per molecule is between 2-30, preferably 3-20, more        preferably 4-12    -   f) Glass transition temperature Tg=220-320K, preferably 230-300,        more preferably 240-290, most preferably 250-280 (as measured by        DSC at heating rate of 10 K/min).

These fatty resins have good easy to clean properties at higher Tg andcrosslink density (ie lower EQW and higher functionality) in combinationwith fatty components.

DETAILED DESCRIPTION OF THE INVENTION

RMA crosslinkable compositions comprise at least one crosslinkablecomponent comprising reactive components A and B each comprising atleast 2 reactive groups wherein the at least 2 reactive groups ofcomponent A are acidic protons (C—H) in activated methylene or methinegroups (RMA donor group), and the at least 2 reactive groups ofcomponent B are activated unsaturated groups (C═C) (RMA acceptor group).These reactive groups react to achieve crosslinking by Real MichaelAddition (RMA) reaction between said at least one crosslinkablecomponents in the presence of a base catalyst (C). Such RMAcrosslinkable compositions are described in EP2556108. Herein a specialcatalyst C is described which is a substituted carbonate catalyst whichdecomposes in a coating layer to generate carbon dioxide whichevaporates from the applied curing coating layer and a strong base whichstarts the RMA crosslinking reaction.

The RMA crosslinkable compositions comprising the resin of the inventioncompositions have a very good balance of working time and service timeand also have improved coating properties like adhesion and appearance.It is believed that the fatty acid backbone helps the RMA crosslinkablecomposition, to penetrate into porous substrates to seal them better andalso to bring out better the vibrancy of colors of the substrate inun-pigmented coatings. It was further found that the RMA crosslinkablecompositions comprising the resin of the invention have good adhesionand have very useful easy to clean properties.

The one or more reactive components A preferably predominantly compriseone type of reactive components, predominantly meaning that more than50, 75, 90 and most preferably 100% of the C—H reactive groups in thecrosslinkable component A are from one type of reactive component A andreactive component A preferably is a malonate, acetoacetate,acetylacetone, acetoacetamide or propionylacetate, most preferably amalonate.

The resin of the invention preferably is 1) a polyol oligomer or polymermodified with fatty acids and reactive component A or a fatty alcohol orfatty acid oil modified with reactive component A or 2) a polyester,polyurethane, acrylic, epoxy or polyether oligomer or polymer or hybridsor mixtures thereof modified with fatty acids and reactive component Aand wherein the fatty acids and reactive component A are preferablybonded with ester bonds or 3) wherein the resin is an oligomer orpolymer polyester, polyurethane, polyether, acrylic, epoxy, or polyolcomprising hydroxyl groups and fatty acids, preferably an alkydcomprising fatty chains which is modified with reactive component A,preferably by esterification or trans-esterification, includingpolyesterurethane, polyesteramide

In general the fatty components, preferably acids have a carbon lengthfrom 4-28, preferably from C6 to C18 and are preferably are derived frombio-based sources, preferably vegetable oil. In a particular embodimentthe fatty acids comprise a C8 to C18 chain with less than 20, 15 or 10wt % of the fatty acids being unsaturated fatty acids. It was found thatthe resin with these fatty acids has improved easy to clean propertiesas demonstrated in the examples. These compositions can be cured byradical cure of components B.

In another embodiment the resin of the invention comprises fattycomponents preferably acids comprising C8 to C18 chains with 20, 25, 30or 40 to 99 wt %, preferably 60 to 99 wt % of the fatty acids beingunsaturated fatty acids. This resin has dual cure properties and can becured by RMA reaction as well as by reaction with the unsaturated bonds,for example by auto-oxidative or actinic radiation crosslinking.

In another embodiment the resin of the invention comprises fatty acidsthat comprise a C8 to C18 chain with hydroxyl groups or fatty acids thatcomprise a C8 to C18 chain with epoxy groups. This resin has dual cureproperties and can be cured by RMA reaction as well as by reaction withthe hydroxyl or epoxy groups, for example by crosslinking reaction witha co-component comprising polyamine, -isocyanate, -epoxy or -hydroxy. Itis noted that multiple cure mechanisms can be used as well bycombinations RMA with 2 or more of unsaturated, hydroxyl or epoxygroups. It is further noted that for dual or multiple cure propertiesC4-C28 or C6-C22 can also be used but C8-C18 is preferred only forpractical reason of availability (coconut oil).

The RMA crosslinkable resin comprises fatty acids preferably in anamount of 5 to 80 wt %, preferably 10 to 60 wt % and most preferably 20to 40 wt % relative to total weight of the RMA crosslinkable resin andcomprises reactive components A in an amount between 1 and 80 wt %,preferably 5 to 70 wt % more preferably 10 to 40 wt % relative to totalweight of the RMA crosslinkable resin.

An advantage of the RMA crosslinkable resin is also that it can be for alarge part based on renewable resources. The fatty acids are preferablyderived from bio-based resources, preferably vegetable oil. In apreferred embodiments the resin is based on alkyd which may have otherbio-based components in particular polyols like glycerol. Ideally theresin may contain at least 30, preferably 40 or 50 wt % of the resinweight of components derived from renewable resources.

The RMA crosslinkable resin preferably has a weight average molecularweight Mw of at least 250 daltons and preferably is a polymer having Mwbetween 250 and 10000, more preferably between 400 and 5000 daltons andpreferably a poly-dispersity between 2 and 5.

The RMA crosslinkable resin must have an acid value below 5, preferablybelow 4, 3, 2 and most preferably below 1 KOH/gr because the RMAcrosslinking reaction is base catalyzed and acid components interferewith the base catalyst C and the acid base reaction between catalyst Cand A and optionally D. The RMA crosslinkable resin is preferablyprepared in a process comprising a) providing a resin comprising fattycomponents, preferably acid esters having an acid value below 5,preferably below 4, 3, 2 and most preferably below 1 KOH/gr and b)adding reactive component A preferably having at least one ester groupand more preferably a malonate ester and 3) reacting at least a part ofthe reactive component A with the resin comprising fatty esters. Thisreaction is preferably a transesterification reaction.

The RMA crosslinkable resin can advantageously be used for themanufacture of—and as component in—a coating composition, an adhesivecomposition or a sealant composition.

The invention also relates to RMA crosslinkable composition comprisingthe RMA crosslinkable resin of the invention as described above andfurther comprising crosslinkable components comprising reactivecomponents B comprising activated unsaturated groups (C═C) (RMA acceptorgroup) which crosslink by Real Michael Addition (RMA) reaction with thecomponents A in the RMA crosslinkable resin in the presence of a basecatalyst (C), wherein reactive component B preferably is an acryloylgroup.

In a particular embodiment the RMA crosslinkable composition comprisesthe RMA crosslinkable resins of the invention comprising fatty acidshaving reactive functional groups, in particular crosslinkable groups,preferably selected from unsaturated groups, epoxy groups or hydroxygroups or combinations thereof, thus providing 2 or more differentcrosslinking mechanisms. The fatty acids having reactive functionalgroups can relatively easily be obtained by derivatising unsaturatedbonds of unsaturated fatty acids. For example amine functional fattyacids would also be possible.

These compositions can be cured by RMA reaction as well as by reactionwith the hydroxyl and/or epoxy groups, for example by crosslinkingreaction with a co-component comprising polyamine, -isocyanate, -epoxyor -hydroxy. The invention accordingly also relates to a method forcuring a coating composition comprising the RMA crosslinkable resindescribed above comprising a combination of two or more crosslinkingreaction steps including a RMA crosslinking reaction step and one ormore other crosslinking reaction steps selected from auto-oxidative,peroxy or radiation crosslinking performed before, during or after theRMA crosslinking reaction and in any order wherein curing can be done byRMA crosslinking and curing by hydroxyl reaction with polyisocyanates orsiloxanes or curing is done by epoxy reaction with amines in any order.

In a particular embodiment the invention relates to a method for curinga coating composition comprising RMA crosslinkable resins in general,but preferably the RMA crosslinkable resins described herein, comprisinga combination of two or more crosslinking reaction steps including a RMAcrosslinking reaction step and a radical curing crosslinking step. Theradical curing step can be a radiation or a thermal initiated radicalcuring step. In the radiation curing step radicals are createdpreferably by UV or with E-beam initiation. It may also be with daylight(VIS) which is also capable of curing. Radiation curing requires agentsthat create radicals on radiation. E-beam does not necessarily requireradical forming agents. In case of thermal initiated radical curing athermal radical initiator is used in the crosslinkable composition.

The order of the two crosslinking steps can vary for different reasons.The radical crosslinking step can be before, during or after the RMAcrosslinking reaction step or combinations thereof as described indetail below.

The inventors have encountered a problem that can occur in curing RMAcrosslinkable coating layers, in particular in thicker coating layers,typically having a dry thickness over 100 micron. The problem is thatthe mechanical and chemical properties of the coating are not as high asexpected. It was found that the curing of the coating layer is nothomogeneous throughout the thickness of the coating layer, in particularthat the coating layer in the vicinity of the air interface have a toolow crosslinking density. It is believed that this occurs as a result ofvitrification through solvent evaporation, which will leave unreactedcrosslinking functionality after full curing of the coating. Thisnegatively properties like mechanical and chemical properties preciselywhere it is important for a coating: at its surface. Once this problemwas identified it was found it could be solved by a subsequent radicalcuring. Therefore in a first embodiment of this method of the invention,the method for curing a coating composition involves a radicalcrosslinking step after the RMA crosslinking reaction step (post radicalcure). This is done preferably with radiation, most preferably UVradiation.

The inventors have encountered another problem that can occur in curingRMA crosslinkable coating layers and in particular in thicker coatinglayers. The problem is that after application of the RMA crosslinkablecoating composition sagging may occur which negatively impactsappearance. This problem could be solved by a radicalcuring/crosslinking step before the RMA crosslinking reaction step. Theinitial crosslinking induced by the radical increases the viscosity theuncured RMA crosslinkable coating layer before the RMA crosslinkingreaction starts. Reactivity moderator D can be used to providesufficient open time to also allow a first radical curing step. Caremust be taken to not use up too much of the component B and disturb theRMA crosslinking with unbalanced stoichiometry. An excess of the radicalcrosslinkable components is preferably used for the amount expected toreact in radical curing to maintain after radical curing a good balanceof RMA reactive components A and B as herein described. This has atleast one of the advantages of preventing sagging and achieving a morehomogeneous crosslinking throughout the coating layer. Therefore in asecond embodiment of this invention, the method for curing a coatingcomposition involves a radical crosslinking step before the RMAcrosslinking step to partially crosslink the coating layer before theRMA crosslinking reaction starts (pre radical cure). This method canalso be used to produce matt or low gloss coatings. The dual cure methodcan also be a combination of the first an second embodiment: pre- andpost cure.

The dual cure method involving both a RMA curing step and a radicalcuring step according to the first or second embodiment or both is alsouseful to coat substrates that need to be formed and where a flexiblecoating is needed, which involves a first curing step and a secondcuring step to increase Tg and XLD (lower flexibility) after thesubstrate forming process.

The first embodiment of the method can also be applied in a specialcircumstance and for another reason in a special third embodiment ofthis method. This method also involves a radical crosslinking step afterthe RMA crosslinking reaction step but is a method for radical curing ofa UV curable coating composition which are typically low viscous, saidUV curable coating composition also comprising RMA crosslinkablecomponents and wherein a RMA crosslinking reaction step preceeds theradical curing step to partially cure the UV curable composition beforethe UV curing starts to quickly increase the viscosity, possibly up toformation of a gel to prevent sagging of the coating composition. Thisis particularly advantageous for UV curing of objects having a complexshape that have shade parts that cannot be easily irradiated. RMAcrosslinkable components are useful in this application because thecrosslinking reaction is very fast.

Compared to conventional radiation curing (UV), the RMA crosslinkingprovides an option for crosslinking shady parts, or thicker pigmentedparts where pigments prevent penetration of UV light to deeper layers.

In the first embodiment the RMA crosslinkable composition comprisescrosslinkable components having components A and B with functionalgroups C—H and C═C within the ranges as herein described. In the secondembodiment the RMA crosslinkable composition comprises crosslinkablecomponents having components A and B wherein functional groups C—H andC═C can be within the ranges as herein described, but preferably have astoichiometric excess of reactive groups C═C in crosslinkable componentB. In the third embodiment the UV curable coating composition comprisesmore than 60 wt %, preferably more than 70, 80 or 90 wt % UV curablecomponents and less than 40, preferably less than 30, 20 or 10 wt % ofRMA crosslinkable components comprising component A, the sum thereofbeing 100 wt %.

The radical curing can be carried out preferably by free radical curingusing UV light, typically 200-400 nm light or electron beam using lowenergy electrons. In UV coatings people use UVA-TLO3 lamps early in theline to partially gel or vitrify the coating followed by full cure withUV-B to adjust the surface and full cure.

Photoinitiator must be added to absorb UV light and generate freeradicals to start reaction between the activated unsaturated bonds, forexample in acryloyl, such as in component B of the crosslinkablecomposition. E-beam curing does not require photoinitiator. Unsaturatedbonds that are not activated such as in fatty acids are not so easy toradiation crosslink. Photoinitiators that can be used are known in theart and include Benzoin alkyl ethers;4,4′-bis(diethylamino)benzophenone; Acetone and other ketones;Benzophenone and Thioxanthenone.

In a particular embodiment dual cure compositions comprise acrylateacceptors as well as methacrylate acceptors. The former will react wellas RMA, the latter not so well, but are very usable for radical cure.

The RMA crosslinkable composition forms the most essential part, i.e.the binder system, of a coating composition. The RMA crosslinkablecomposition may further comprise additives which are relevant for thecrosslinking reaction of the binder system, for example one or morereactivity moderators D, an alcohol as pot life improver, water,reactive solvents that are reactable with reactive component A or B, butalso other additives like organic solvents T, sag control agents E,adhesion promotors P, and usual other coating additives like levelingagents, UV stabilisers, pigments, fillers etc. Water may improve potlife but preferably the water content is at most 5 wt %.

The catalyst C is mixed in shortly before the application and thereforethe RMA crosslinkable composition is preferably in the form of a kit ofparts comprising one or more parts I comprising a base catalyst C forinitiating the RMA crosslinking reaction and one or more parts II notcomprising said base catalyst C and comprising other remainingcomponents of the RMA crosslinkable composition.

The invention accordingly also relates to a process for the coating of asubstrate surface comprising mixing, shortly before application, the atleast one parts I and II of the kit of parts of the RMA crosslinkablecomposition and applying a layer of the resulting composition on thesubstrate surface.

The invention also relates to the use of the RMA crosslinkablecomposition of the invention in coating compositions for application ofa top-coating over a conventional sealer layer which is based on one ormore resins including epoxy, phenolic, silane, silicone, acrylics,polyurethane, polyurea, polyaspartic resins and their hybrids.

Good results were obtained using the RMA crosslinkable composition forcoating a wood floor, in particular a gymnasium floor, a concrete floor,a vinyl floor, terrazo floor, cork floor, phenolic floor or a metalfloor. It was further found that the RMA crosslinkable composition canbe used for direct coating on concrete floors without a sealer layer,which is very advantageous compared to polyol/isocyanate curing bindersystems.

The invention relates in particular to the use of the above describedRMA crosslinkable composition wherein the RMA crosslinkable resincomprises fatty acids with C8 to C18 chains with less than 20, 15 or 10wt % unsaturated fatty acids for the manufacture of a coatingcomposition having easy to clean properties, for use in particular ingraffiti resistant coatings and in sanitizable coatings for hospital andtoilet walls and floors. The examples show a distinct advantage overknown RMA coatings.

RMA crosslinkable composition comprising the resin of the invention aresuitable for a variety of coatings applications. These fatty acidmodified resins containing reactive components A, in particularmalonates, are suitable for use in a variety of coatings applicationsforming fast-drying, highly cross-linked films that can be formulatedfor tunable pot-life and good open-time balance.

Floor coatings with significantly longer pot life could be achievedhaving outstanding chemical resistance and abrasion resistance. Thisapplies in particular to those compositions including effective amountsof reactivity moderating component D, achieving long potlife and shortdry to touch time (or working time and service time). The inventionfurther provides RMA compositions for use in floor coating compositionswith low VOC, which is advantageous in view of Quality EnvironmentSafety & Health (QESH) requirements, in particular for compositionscontaining specific reactive solvents which reduce viscosity but notcontribute to VOC which is particularly useful for compositions withhigh particulate filler contents.

The composition presented in this invention is a two-pack (2K) system. Avariety of 2K synthetic resin systems are available with the dominanttechnologies being acid-catalyzed amino cross-linked alkyds, epoxy-aminesystems and polyol-polyisocyanate systems. The RMA crosslinkable resinand coating compositions thereof is faster drying plus develops hardnessmuch more quickly than any of these other technologies. Plus, thisinvention is not sensitive to moisture as are the polyol-isocyanatesystems. Pot-life is similar to amino cross-linked alkyds but is muchlonger than the epoxy-amine or polyol-polyisocyanate systems. Thisinvention retains the good appearance and flow properties of aminocrosslinked alkyds, but is formaldehyde-free. Epoxy-amine andpolyol-isocyanate technologies both use chemicals that have questionabletoxicological profiles: bis-phenol A/F in epoxy resins, amine curingagents, monomeric diisocyanate in polyisocyanate hardeners. Compared tothese other 2K systems, this invention has a more favorabletoxicological profile.

This invention also has applications in the areas where hygienicenvironments need to be maintained like hospitals, nursing care, surgerycenters, rest rooms etc. Also high traffic public areas like schools,malls, airports need to be constantly cleaned and maintained well. Anycoating that protects the surface that has the “easy to clean”characteristics provides advantage for the facility operator and owner.Moreover the coating will resist stains and aesthetically look good. Theoutstanding easy-to-clean property of the RMA crosslinkable resin of theinvention is a very interesting advantage for coating applications inthe above mentioned areas.

DETAILED DESCRIPTION OF THE INVENTION

Alkyd resins have been utilized in the coatings industry for years. Theyoffer excellent applications properties including good flow, appearanceand surface wetting to a variety of substrates. This is due to theoil/fatty acid content of alkyds which distinguish them from “oil-free”polyesters. The oils/fatty acids present in alkyds help to reduce thesurface tension of the resin while internally plasticizing the resingiving flexibility and resistance to cracking/shrinkage with aging ofthe coating film.

The fatty acids and oils available for use in alkyds allows selectivitywith regards to properties and functionality of the finished polymer.Oils and fatty acids with a higher level of unsaturation (e.g., linseed,tung) generally give better oxidative cure owing to higher levels oflinoleic and linolenic acids. This unsaturation can also act as areactive moiety in radiation curing additionally.

Oils/fatty acids with a higher level of conjugated unsaturation (e.g.,dehydrated castor oil) will offer an even higher level of oxidative cureand better reactivity in radiation curing since the conjugation allowsresonance stabilization of radicals creating during oxidation andradiation curing. So, the type of oil/fatty acid allows the formulatorselectivity in terms of drying and curing properties.

Oils/fatty acids with lower levels of unsaturation, the so-calledsemi-drying oils (e.g. soybean oil, tall oil, sunflower oil) can stillcure oxidatively and via radiation curing but at a lower level. Thisallows the formulator to incorporate harder segments and balanceoxidative properties and radiation curing properties while stillmaintaining an open film surface. This can be advantageous for goodsolvent release.

Highly saturated oils/fatty acids (e.g. coconut oil, palm kernel oil,tallow) allow the formulator to utilize the good properties that oilsimpart in terms of flexibility and good film flow/appearance with alower level yellowing upon aging of the coating. Plus, post-cure viaoxidative cure can be reduced or eliminated with highly saturatedoils/fatty acids which is desirable since in some instances this canlead to cracking and delamination. This is particularly important onmore dynamic substrates such as wood. Functional oils such as castor(hydroxyl), vernonia (epoxy, naturally occurring), and epoxidizedsoybean oil (industrially produced) allow the formulator to buildvarious crosslinking and dual-cure moieties into the alkyd polymer.

Reference is made to EP2556108 and EP2764035 for detailed description ofcomponents in the RMA crosslinkable composition A, B C or D, theirpreparation, the amounts used in the RMA crosslinkable composition aswell as for measurement methods and definitions and the descriptionthereof is hereby incorporated by reference and applicable unlessdescribed otherwise herein. Most important features are described belowin summary.

It is preferred that reactive component A is malonate or acetoacetateand reactive component B is acryloyl. It is preferred that the one ormore reactive components A in the crosslinkable component predominantlycomprise one type of reactive components, predominantly meaningpreferably more than 50, 75, 90 and most preferably 100% of the C—Hreactive groups in crosslinkable component A are from one type ofreactive component A, preferably from malonate or acetoacetate and mostpreferably consisting predominantly of malonate and acetoacetate oracetylacetone as the remainder component A. The most preferred reactivecomponent B is an acryloyl.

The reactive components A and B are preferably build into a polymerchain or pending or terminal pending on a polymer chain. The RMAcrosslinkable resin of the invention is one of the crosslinkablecomponents comprising reactive component A. Optionally othercrosslinkable components comprising reactive component A can be present.Preferably, the one or more other crosslinkable components are one ormore polymers chosen from the group of polyesters, alkyds,polyurethanes, polyacrylates, epoxy resins, polyamides and polyvinylresins which contain components A or B in the main chain, pendant,terminal or combinations thereof.

The relative amounts of the crosslinkable components in the RMAcrosslinkable composition are chosen such that the molar ratio ofactivated unsaturated reactive group C═C in reactive component B to theactivated acidic reactive groups C—H in reactive component A is between0.5 and 2 and preferably between 0.75-1.5 or 0.8-1.2.

In case a reactive solvent is present having 2 C—H reactive groups (forexample malonate) then these are also included in the total amount ofC—H in the above ratio as they are crosslinkable components. If howevermonofunctional reactive solvents are used the C—H nor the C═C is takeninto account for calculation of the ratio as they do not form part ofthe crosslinked network. Also the total amount of monofunctionalmaterial should be low, otherwise it will negatively affect coatingproperties. Preferably the total amount monofunctional reactive solventis less than 10, preferably less than 5, 3 or even 2 wt %.

The RMA crosslinkable composition preferably further comprises areactivity moderator D comprising an X—H group that is also a Michaeladdition donor reactable with component B under the action of catalystC, wherein X is C, N, P, O or S or an alcohol with 2 to 12 carbon atomsor both for improving open time and hence working time of application ofthe floor coating composition on a floor.

The X—H group in component D, preferably an N—H group containingcomponent, has a pKa (defined in aqueous environment) of at least oneunit, preferably two units, less than that of the C—H groups inpredominant component A, preferably the pKa of the X—H group incomponent D is lower than 13, preferable lower than 12, more preferablylower than 11, most preferably lower than 10; it is preferably higherthan 7, more preferably 8, more preferably higher than 8.5.

The component D preferably comprises a molecule containing the N—H aspart of a group —(C═O)—NH—(C═O)—, or of a group —NH—(O═S═O)— or aheterocycle in which the nitrogen of the N—H group is contained in aheterocyclic ring preferably chosen from the group of a substituted orunsubstituted succinimide, glutarimide, hydantoin, triazole, pyrazole,immidazole or uracil, preferably chosen from the group of succinimides,benzotriazoles and triazoles.

The component D is present in an amount between 0.1 and 10 wt %,preferably 0.2 and 7 wt %, 0.2 and 5 wt %, 0.2 and 3 wt %, morepreferably 0.5 and 2 wt % relative to the total amount of thecrosslinkable components A or B and component D. The component D ispresent in such amount that the amount of X—H groups in component D isno more than 30 mole %, preferably no more than 20, more preferably nomore than 10, most preferably no more than 5 mole % relative to C—Hdonor groups from component A present in the crosslinkable polymer.

In case components D are present which also comprise reactive groups X—Hand can react with B, the molar ratio of activated unsaturated reactivegroup C═C in reactive component B to the total number of reactive groupsC—H in reactive component A and reactive groups X—H in component D isbetween 0.3 and 3, preferably 0.5-2 and even more preferably 0.75-1.5 or0.8-1.2.

As described the RMA crosslinkable composition comprises catalyst Cwhich is a base and mixed in only shortly before use of the flooringcomposition. The catalyst C can be a carbon dioxide blocked strong basecatalyst, preferably a quaternary alkyl ammonium bi- or alkylcarbonate(as described in EP2556108). As this catalyst generates CO₂ it ispreferred for use in coating layers with a thickness up to 500, 400,300, 200 or 150 micrometer.

For compositions that are to be used in thick layers, in particular inhigh build and highly filled floor coating layers, the catalyst C ispreferably a homogeneously active strong base catalyst, i.e. not of thesurface deblocking type as described above. Preferably such catalyst isused in coating layers with a thickness from 150, 200 or 300 up to 2000,1500, 1000 or 10,000 micrometer. An upper limit in thickness is inpractice determined only by cost and intended use.

A suitable homogeneous catalyst C is the reaction product of an epoxidewith a tertiary amine as described in EP0326723. The tertiary amine andepoxy components are combined during or shortly before combination ofall components. Alternatively either the tertiary amine or epoxy aremixed with the combined components A and B and the remaining constituentof the catalyst is added thereto. The preferred epoxide componentscontain the epoxide group as glycidyl esters, glycidyl ethers, orepoxidation products of alpha olefins. A preferred tertiary amine istriethylene diamine.

A preferred homogeneous catalyst C is a salt of a basic anion X— from anacidic X—H group containing compound wherein X is N, P, O, S or C, andwherein anion X— is a Michael Addition donor reactable with component Band anion X— is characterized by a pKa(C) of the corresponding acid X—Hof more than two units lower than the pKa(A) of the majority component Aand being lower than 10.5. Details of this catalyst are described inWO2014166880A1, which is hereby incorporated by reference. Thiscatalysts C is especially useful in applications in which there is nolarge surface available for allowing CO₂ to evaporate such as in thecase of thick films applications.

In this case catalyst C is a salt according to formula Cat“1” X″,wherein Cat“1” is a non-acidic cation, with no ability to inhibit thecrosslinking reaction of components A and B. This implies that, if anyprotons are associated with the cation, their acidity does not exceedthat of the dominant C—H functions in component A, by more than twounits, preferably not more than 1 and more preferably not more than 0.5pKa unit. Examples of useful cations include inorganic cations,preferably alkaline or alkaline earth metal cations, more preferably K+,Na+ and Li+, or organic cations like tetra-alkylammonium andtetra-alkylphosphonium salts, but also cations that do have a proton butare extremely non-acidic, for example protonated species of stronglybasic organic bases as e.g. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU),1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) or tetra-methylguanidine. Thesebases would be able to initiate the crosslinking reaction betweencomponents A and B but do not interfere with the reaction (inhibiting)in their protonated form.

An additional advantage of these catalyst components C is that they canbe significantly less expensive than the known RMA latent base catalyst.For example, in most circumstances the cations that are required incarbon dioxide blocked latent base catalyst are of thetetra-alkylammonium type which are much more expensive. Because of theanion X— the salt component C has sufficient solubility even with simpleand inexpensive cations like potassium.

In view of the fact that the RMA crosslinking reaction is basecatalyzed, acidic components should not be used in the composition suchthat the acid base reaction between catalyst C and A and optionally D isnot interfered. Preferably the composition is free of acidic components.

The RMA composition may comprise one or more organic solvents T requiredfor dissolving certain components or for adjusting the RMA compositionto an appropriate handling viscosity (eg for spraying application).Organic solvents for use in RMA crosslinkable compositions are commoncoating solvents that do not contain acid impurities like alkylacetate(preferably butyl or hexyl acetate), alcohol (preferably C2-C6 alcohol),N alkylpyrrolidine, glycolether, Di-propylene Glycol Methyl Ether,Dipropylene Glycol Methyl Ether, Propylene Glycol Methyl Ether Acetate,ketones etc.

The amount of volatile solvent can be between 0 and 60, 50 or 40 wt %but in view of QESH preferably the composition has a low volatileorganic compounds (VOC) content and therefore the amount of volatileorganic solvent is preferably less than 20, 15, 10, 5 and mostpreferably less than 2 or even 1 wt % relative to the total of thecrosslinkable components A and B.

In particular where a low viscosity and a low VOC is required it ispreferred that the RMA crosslinkable composition comprises one or morereactive solvents which react with crosslinkable components A or B. Theone or more reactive solvents are preferably selected from the group ofmonomeric or dimeric components A, monomeric or dimeric components B,compounds A′ having only 1 reactive acidic protons (C—H) in activatedmethylene or methine groups, compounds B′ having only 1 reactiveunsaturated groups (C═C), most preferably acetoacetate or malonate, mostpreferably malonate. The total amount of volatile organic solvent plusreactive solvents is between 0 and 30 wt % and the volatile organicsolvent is less than 5 wt % relative to the total weight of the RMAcomposition.

The RMA crosslinkable composition can be used for different applicationsincluding coatings, adhesives, inks, synthetic resin flooring or as abinder in structural composites, but preferably is a coating composition(i.e. a paint) optionally comprising further usual coating additives asmay required for the envisaged application.

EXAMPLES

The following is a description of certain embodiments of the invention,given by way of example only.

The examples relate to flooring compositions comprising a RMAcrosslinkable alkyd resin and a carbondioxide blocked base catalystwhich is a salt of a quaternary ammonium and an alkylsubstitutedcarbonate. Table 1 shows the catalyst composition.

Several malonated alkyds were synthesised as described in the examples1-5 below. In Ex 1 the fatty acid was coconut fatty acid and reactivecomponent A was dimethyl malonate. This resin is mainly based onsaturated fatty acids with low yellowing tendency. In Ex 2 the fattyacid was Soybean oil fatty acid and reactive component A was diethylmalonate. This resin has significant amount of unsaturation and can beused in RMA cure and dual cure applications, in particularauto-oxidation as the secondary cure mechanism. In Ex3 and Ex 4 thefatty acid was based on castor oil and reactive component A was dimethylmalonate. This resin has the functional hydroxyl group in the chain andcan be used in isocyanate-hydroxyl cure along with RMA cure. Otherhydroxyfunctional crosslinkable components can have high hydroxylvalues, and can be used in NCO (co-)cure. This is not specific to the OHfunctional fatty resin. In Ex 5 the fatty acid was coconut fatty acidand epoxidized Soybean methyl ester and reactive component A wasdimethyl malonate. This resin has the functional epoxy groups in thechain and can be used in epoxy-amine cure along with RMA cure.

The components B of the RMA crosslinkable composition are TMPTA orDiTMPTA, which were mixed in the formulation as a pre-mix with thepigment paste or separately or both. Table 2 lists the components of thecoating compositions.

Example1 Malonated Alkyd 1

A three-liter, four-necked reaction flask equipped with a condenser,agitator, heating mantle, sampling tube, thermocouple attached to athermowatch and toluene-primed Dean-Stark trap was charged with 349.91parts coconut fatty acid, 395.47 parts trimethylolpropane, 62.73 partspentaerythritol, 100.10 parts of phthalic anhydride, 93.60 parts ofAdipic acid and 0.94 parts of dibutyltin oxide and sparged with nitrogenat 0.5 standard cubic feet per hour (SCFH) for 15 minutes withoutagitation followed by 15 minutes with agitation. The reaction mixturewas then heated to 450-455° F., discontinuing the nitrogen flow at theonset of distillation. The mixture was held at 450-455° F. for an acidvalue of <1 adding toluene as needed to maintain a steady reflux. Oncethe acid value was reached, the mixture was cooled to 180° F. under anitrogen blanket. 742.89 parts of dimethyl malonate were added to thereaction mixture, a packed column was added to the reactor and theDean-Stark trap drained. The resin was heated to 330° F. and held untilmethanol distillation ceased. The nitrogen sparge was then increased to2.0 SCFH to remove the azeotrope solvent and the resin cooled andfiltered. The resulting malonate-functional resin contained 11.4%residual dimethyl malonate and had a Gardner-Holdt viscosity of Z1-Z2with an acid value of 0.5 and an APHA color of 98. The number averagemolecular weight was 1490 with a weight average molecular weight was8530.

Example 2 Malonated Alkyd 2

A four-necked reaction flask equipped with a condenser; agitator;heating mantle; addition funnel; thermocouple attached to a control box(Love control series 32A); and primed Dean-Stark trap with toluene, wascharged with 26.4 parts (by weight) of Soybean oil fatty acid, 29.9parts of trimethylol propane, 4.7 parts of pentaerythritol, 14.3 partsof phthalic anhydride, 0.07 parts of dibutyltin oxide, and heated under0.5 SCFH (standard cubic feet per hour) (0.014 m3 hr-1) nitrogen flow to165° C. At 165° C., water started to distil azeotropically. The reactiontemperature was increased to 230° C. and maintained at such temperatureuntil an acid value of <1.0 was attained. The alkyd was cooled to 110°C. To this resin, 37.7 parts of diethyl malonate was added and thetemperature was increased to 150° C. Minimum amount of toluene was addedto distil ethanol azeotropically. At 150° C., ethanol started to distilout. The reaction temperature was increased to 180° C. and maintained atthis temperature to collect all the ethanol. Once the ethanol stopcoming, the reaction was cooled; Nitrogen flow was increased to 2 SCFH(0.057 m3 hr-1) to remove all the toluene.

The resulting resin had 96% non-volatile material (NVM); density 9.38lb/gallon, Gardener-Holdt viscosity of Z6-Z7, an acid value of 0.37; anumber average molecular weight (Mn) of 2100; a weight average molecularweight (Mw) of 9000; and a polydispersity of 4.3.

Example 3 Malonated Alkyd 3

A three-liter, four-necked reaction flask equipped with a packed column,toluene-primed Dean-Stark Trap, condenser, agitator, heating mantle,sampling tube and thermocouple attached to a thermowatch was chargedwith 917.97 parts of castor oil, 532.20 parts of trimethylolpropane,108.30 parts of pentaerythritol, 327.60 parts of phthalic anhydride and2.50 parts of dibutyltin oxide and the contents sparged with nitrogen at0.5 SCFH for 15 minutes without agitation and another 15 minutes withagitation. The contents of the reactor were then heated to 375-380° F.discontinuing the nitrogen sparge once distillation began. The mixturewas held at 375-380° F. for an acid value of <1 adding toluene as neededto maintain a steady reflux. Once the acid value was reached the reactorwas cooled to 300° F. with a 0.5 SCFH nitrogen blanket. 831.70 parts ofdimethylmalonate were then added to the resin and the Dean-Stark trapdrained. The reaction mixture was then heated to 330° F. collecting themethanol as it distilled off and held at 330° F. until the reaction wascomplete. The packed column was then removed and the nitrogen sparge wasincreased to 2.0 SCFH to distill off the azeotrope solvent at whichpoint the reaction mixture was cooled and filtered. The resultingmalonate-functional alkyd resin contained 4.1% residual dimethylmalonate. The resin had a viscosity of 350,000 cPs and an APHA color of332.

Example 4 Malonated Resin 4

A three-liter, four-necked reaction flask equipped with a packed column,condenser, unprimed Dean-Stark trap, agitator, heating mantle,thermocouple attached to an automatic temperature controller was chargedwith 919.75 parts castor oil and 369.98 parts of dimethyl malonate andheated to 330° F. under a nitrogen blanket at 0.5 SCFH. The nitrogenflow was discontinued at the onset of distillation. The resin was heldat 330° F. until methanol distillation ceased at which point it wascooled and filtered. The resulting resin was 90.5% NVM in dimethylmalonate with a viscosity of 600 cps, an acid value of 1.5 and an APHAcolor of 551.

Example 5 Malonated Alkyd 5

A four-necked reaction flask equipped with a condenser; agitator;heating mantle; addition funnel; thermocouple attached to a control box(Love control series 32A); and primed Dean-Stark trap with toluene, wascharged with 21.4 parts (by weight) of coconut fatty acid, 29.2 parts oftrimethylol propane, 11.6 parts of phthalic anhydride, 0.07 parts ofdibutyltin oxide, and heated under 0.5 SCFH (standard cubic feet perhour) (0.014 m3 hr-1) nitrogen flow to 165° C. At 165° C., water startedto distil azeotropically. The reaction temperature was increased to 230°C. and maintained at such temperature until an acid value of <1.0 wasattained. The alkyd was cooled to 110° C. To this resin, 30.9 parts ofdimethyl malonate was added and the temperature was increased to 180° C.Minimum amount of toluene was added to distil methanol azeotropically.At 150° C., methanol started to distil out. The reaction temperature waskept at 180° C. to collect all the methanol. Once the ethanol stopcoming, the reaction was cooled to 110° C. To this resin 20.2 parts ofmethyl epoxy soyate is added. The temperature increased to 180° C.Methanol started to distill out due to the transesterification of methylester at the chain end. The reaction was held at 180° C. to distill outall methanol. The nitrogen flow was increased to 2 SCFH (0.057 m3 hr-1)to remove all the toluene while cooling. The epoxy functional malonatedalkyd was filtered and stored. The resulting resin had 98% non-volatilematerial (NVM); density 9.40 lb/gallon, Gardener-Holdt viscosity ofZ5-Z6, an acid value of 0.42; a number average molecular weight (Mn) of2500; a weight average molecular weight (Mw) of 8500; and apolydispersity of 3.4.

Example A Preparation of Catalysts 1-3

The catalysts 1 and 2 are carbondioxide blocked tetrabutyl ammoniumethyl- and methylcarbonate catalysts respectively and were prepared asdescribed in EP2556108 (catalyst C5). The composition is listed in Table1:

Component Catalyst 1 Catalyst 2 Aqueous TBAH 44.60 0 (55%) TBAH (40%) in0 80 Methanol DI Water 4.90 0 Diethylcarbonate 20.10 0 Dimethylcarbonate0 17.2 n-propanol 30.40 0 Methanol 0 13

Preparation of Catalyst 3

Catalyst 3 is a homogeneous base catalyst according to WO2014166880A1. Amagnetic stirrer was put into a flask containing 74.26 g of ethanol.With gentle mixing, 17.49 g of benzo-triazole was added and then 8.25 gof KOH was slowly added. The solution was warmed to 49° C. and mixed fortwo hours to make KBZT catalyst (Catalyst 3). The base concentration wasdetermined by titration to be 1.324 meq/g.

Coating Formulations were prepared from the components mentioned inTable 2 below by mixing the components and pre-dissolved components asindicated. The coating formulations do not contain catalyst yet. This isadded later. The usual coating additives not explicitly identified anddescribed are well known commercially available components forlevelling, anti-foaming (Foamstar ST-2446), surfactants (Byk 310: 3151:4), colorants (Chroma Chem 844-9955), surface modifiers (SilmerACR-D2).

TABLE 2 Paint Formula A B C D E F G H Malonated Coconut-Alkyd 1 41.3330.43 44.61 15.57 47.3 47.08 31.03 0 Malonated Soya-Alkyd 2 0 0 0 0 0 00.00 48.24 Tri AcetoAcetate 7.29 0.19 0 0 8.32 0 0.20 8.48 Pigment Paste1* 0 59.23 0 0 0 0 60.40 0 Miramer M300 15.42 0 0 0 35.25 0 0.00 33.96Miramer M410 18.83 0.13 22.92 0 0 24.19 0.13 0 Setalux 17-7101 (n- 0 0 084.33 0 0 0.00 0 butylacetate)** Silmer ACR-D2 0.12 0.09 0.09 0.1 0.050.16 0.09 0.06 Pre-dissolve 1,2,4-Triazole 0 0.35 0 0 0 0 0.51 0N-Methyl Pyrrolidone 0 0.56 0 0 0 0 0.83 0 Subsequently add ChromaChem844-9955 0 0 0 0 0 0 0.99 0 Methyl Propyl Ketone 17.02 9.01 32.38 0 0 00.00 0 n-Butyl Acetate 0 0 0 0 0 28.56 0.00 0 2-Propanol 0 0 0 0 0 00.00 9.26 n-Butanol 0 0 0 0 9.08 0 5.82 0 TOTAL 100.0 100.0 100.0 100.0100.0 100.0 100.0 100.0 *Pigment Paste 1 mix 32.0% of Miramer M410 with65.1% of Kronos 2310 and 2.9% of disperbyk 163 and grind until theparticle size is smaller than 10 μm A **Polymeric Acryloyl

Example B1

100 grams of Formulation A was mixed with 5.82 grams of Catalyst 3 andthen applied onto a steel panel. The paint was thoroughly dry (method?)after 40 minutes. The potlife of the mixed paint was less than 1 hour.The next day Konig Pendulum Hardness was determined to be greater than30 seconds. MEK resistance was determined to be greater than 100double-rubs hence shows good chemical resistance.

Example B2

100 grams of Formulation B was mixed with 6.49 grams of Catalyst 3 andthen applied onto a steel panel. The paint was thoroughly dry after 40minutes. The potlife of the mixed paint was less than 1 hour. The nextday Konig Pendulum Hardness was determined to be greater than 40seconds. MEK resistance was determined to be greater than 100double-rubs hence shows good chemical resistance.

Example C1

100 grams of Formulation C was mixed with 2.72 grams of Catalyst 2 and0.5 g of photo-initiator Darocur 4265 and then applied onto a steelpanel. The panel was thoroughly dry after 40 minutes. The potlife of themixed paint was over than 4 hours. The panel was stored in the darkovernight. The next day half of the panel was masked and the whole panelwas exposed to UV light. Konig Pendulum Hardness was determined; theun-exposed paint had a hardness of 24 seconds and exposed area had ahardness of 29 seconds. The percent residual Acryloyl was determined tobe 57% for the un-exposed paint and 44% for the exposed paint.

Example C2

100 grams of Formulation D was mixed with 2.72 grams of Catalyst 2 and0.5 g of photo-initiator Darocur 4265 and then applied onto a steelpanel. The panel was thoroughly dry after 40 minutes. The potlife of themixed paint was over than 4 hours. The panel was stored in the darkovernight. The next day half of the panel was masked and the whole panelwas exposed to UV light. Konig Pendulum Hardness was determined; theun-exposed paint had a hardness of 22 seconds and exposed area had ahardness of 41 seconds. The percent residual Acryloyl was determined tobe 28% for the un-exposed paint and 19% for the exposed paint. Hence theincreased conversion of the double bonds was determined to be due toexposure to UV radiation of the panels and the hardness had increasedMEK resistance was determined to be greater than 100 double-rubs henceshows good chemical resistance.

Example D1

100 grams of Formulation E was mixed with 5.12 grams of Catalyst 1 andthen applied onto a steel panel. The paint was thoroughly dry after 40minutes. The potlife of the mixed paint was over 4 hours. The next dayKonig Pendulum Hardness was determined to be greater than 40 seconds.MEK resistance was determined to be greater than 100 double-rubs henceshows good chemical resistance.

Example D2

100 grams of Formulation F was mixed with 3.49 grams of Catalyst 2 andthen applied onto a steel panel. The paint was thoroughly dry after 40minutes. The potlife of the mixed paint was over 4 hours. The next dayKonig Pendulum Hardness was determined to be greater than 20 seconds.MEK resistance was determined to be greater than 100 double-rubs henceshows good chemical resistance.

Example D3

100 grams of Formulation G was mixed with 2.85 grams of Catalyst 1 andthen applied onto a steel panel. The paint was thoroughly dry after 30minutes. The potlife of the mixed paint was over 4 hours. The next dayKonig Pendulum Hardness was determined to be greater than 40 seconds.MEK resistance was determined to be greater than 100 double-rubs henceshows good chemical resistance.

Example D4

100 grams of Formulation H was mixed with 5.14 grams of Catalyst 1 andthen applied onto a steel panel. The paint was thoroughly dry after 40minutes. The potlife of the mixed paint was over 4 hours. The next dayKonig Pendulum Hardness was determined to be greater than 40 seconds.MEK resistance was determined to be greater than 100 double-rubs henceshows good chemical resistance.

A Pigmented Formulation Z, Curable by RMA, Was Formulated as IndicatedBelow.

Malonated Polyester MPE1

MPE1 is prepared as follows: Into a reactor provided with a distillingcolumn filed with Raschig rings were brought 382 g of neopentyl glycol,262.8 g of hexahydrophthalic anhydride and 0.2 g of butyl stannoic acid.The mixture was polymerised at 240° C. under nitrogen to an acid valueof 0.2 mg KOH/g. The mixture was cooled down to 130° C. and 355 g ofdiethylmalonate was added. The reaction mixture was heated to 170° C.and ethanol was removed under reduced pressure. The resin was furthercooled and diluted with butyl acetate to 85% solids, to yield a materialwith OH value 16 mg KOH/g, GPC Mn 1750, and a malonate equivalent weightof 350 (active C—H EQW 175).

For the MPE1S material, the synthesis of MPE1 was used, now adding 11.2g of succinimide at 140C to allow full dissolution.

The catalyst 4 (CAT4) composition (base content 0.928 mmole/g)

Component Catalyst C Aqueous TBAH 100 (55%) Diethylcarbonate 45.1n-propanol 181

Component Paint Z MPE1 139.4 MPE1S 192.2 Pigment paste* 565.5Pre-dissolve: 1,2,4-triazole 4.8 n-propanol 27.0 Subsequently add Byk310:315 1:4 2.8 Tinuvin 292 4.6 *The composition of pigment paste: 320.3grams of DiTMPTA, 650.7 g of Kronos 2310 pigment, with 29 g of Disperbyk163

Next, the formulations A, B and C were made. DEAEA stands for2-(diethylamino)ethylacrylate, functioning as coinitiator withbenzophenone.

P-Z CAT4t Propanol BuAc Benzophenone DEAEA Total Sample (g) (g) (g) (g)(g) (g) (g) A 50 1.33 2.08 2.95 0 0 56.36 B 25.00 0.67 1.04 1.48 0.120.17 28.48 C 25.00 0.67 1.04 1.48 0.36 0.51 29.06

Films were applied to be cured under ambient conditions, either at a drylayer thickness of approximately 50 mu (index 2), or of 75 mu (index 3).Typically in this formulation, acryloyl conversion can be determined byFTiR (809 cm⁻¹ C═C peak integration) to be high (>90%) at the substrateside, but limited at the outermost top surface. After a day of ambientdrying in daylight, the following values were determined

Sample Top Conversion (%) A2 47 A3 43

After a day of drying in daylight, this was also done for the B and Ccompositions including the photoinitiating ability; also, these werechecked again after a 30 minutes exposure to a UV lamp (CleanLight 75watt, UV C, 30 cm distance). It can be seen that after a day in daylighttop side conversions are higher than the comparative examples A2 and A3.Additional UV exposure lead to a further rise in conversion. A higherconversion of the outermost part of the film, through additional radicalreaction, will lead to a higher Tg and XLD, and accompanied expectedbetter chemical and mechanical resistances.

Top Top UV time Conversion UV time Conversion Sample (mins) (%) Sample(mins) (%) B2 0 65 B3 0 58 B2 30 72 B3 30 61 C2 0 62 C3 0 57 C2 30 71 C330 71

TABLE 3 Paint Formula I J K L M N Malonated 58.60 0 0 Alkyd 6 Malonated0 59.76 0 0 Alkyd 7 Malonated 0 0 59.76 0 Alkyd 8 AcAc Alkyd 11 59.72Malonated 59.48 Alkyd 9 Malonated 59.48 Alkyd 10 Tri 0 0 0 0 0 0AcetoAcetate Pigment 0 0 0 0 0 0 Paste 1* Miramer M300 29.69 30.28 30.2831.23 30.28 30.28 BYK 3550 0 0.29 0.29 0.27 0.27 0.27 Pre-dissolve1,2,4-Triazole 0 0 0 0 0 0 Subsequently add n-Butyl Acetate 4.23 2.042.04 1.15 2.34 2.34 n-Propanol 7.48 7.63 7.63 7.63 7.63 7.63 n-Butanol 00 0 0 0 0 TOTAL 100.0 100.0 100.0 100.0 100.0 100.0 *Pigment Paste 1 mix32.0% of Miramer M410 with 65.1% of Kronos 2310 and 2.9% of Disperbyk163 and grind until the particle size is smaller than 10 μm A

Use Examples D5 and D6 for Dual Cure (Isocyanate and RMA Cure CoatingExamples) Example D5

100 grams of Formulation I was mixed with 3.7 grams of Catalyst 2 andthen applied onto a steel panel. The paint was observed to be thoroughlydry after 40 minutes. MEK resistance was determined to be 137double-rubs which shows good chemical resistance.

Example D6

100 grams of Formulation I was mixed with 3.7 grams of Catalyst 2 and 49g of Desmodur N3390 isocyanate trimer and mixed thoroughly. This paintwas applied to a steel panel. The paint was observed to be thoroughlydry after 40 minutes. MEK resistance was determined to be greater than230 double-rubs which shows good chemical resistance. The followingtable illustrates why the malonate group is the preferred source of —CHfor the polymers claimed in this patent.

In addition to malonate the acetoacetate moiety can also be used incombination with the malonate groups in the polymer up to a level of 30%acetoacetate to adjust pot-life and dry-time. Above 30% acetoacetatemodification in the polymer the films made with these polymers show anunacceptable level of yellowing. In all the four formulations shownbelow the —CH equivalent weight is kept constant at 175 (regardless ofthe —CH source) with a hydroxyl equivalent weight of 550.

To prepare coating formulations D7 to D10, 5.32 g of Catalyst 1 wasadded to 100 g each formulations I, M, N and L and mixed well. They werethen applied on pre-treated steel substrate and evaluated.

% active —CH group Paint Paint in the resin Color Stage 3 MEK FormulaFormulations prepared CH Hydroxyl (RT Dry KPH Double MEK Double withwithout using Equivalent Equivalent Potlife cure) (min.) (air KPH rubsair rubs baked catalyst catalyst Acetoacetate weight Weight (hours) “b”Clear dry) (baked) dry 150 F. D7 I 0 175 550 7 2.14 24 48 88 158 230 D8M 10 175 550 2 4.86 47 69 62 221 284 D9 N 30 175 550 1 5.51 51 79 59 208320 D10 L 100 175 550 <1 8.08 >60 37 40 204 226

The effect of —OH groups in the polymer backbone can be illustrated inthe table below. As the amount of —OH groups decreases the pot lifedecreases and drytime shortens. OHV 140 corresponds to EQW 400. Doublethe EQW means half the OHV.

To prepare coating formulations D7, D11 and D12, 5.32 g of Catalyst 1was added to 100 g each formulations I, J and K and mixed well. Theywere then applied on pre-treated steel substrate and evaluated.

Paint Paint Stage 3 MEK Formula Formulations CH Hydroxyl Pot- Dry KPHDouble MEK Double with without Equivalent Equivalent life (min.) (airKPH rubs air rubs baked catalyst catalyst weight Weight (hours) Cleardry) (baked) dry 150 F. D7 I 175 550 7 24 48 88 158 230 D11 J 175 1000 47 79 89 207 276 D12 K 175 2000 3.5 2 46 79 190 220

What is claimed is:
 1. A method for curing of a coating of an RMAcrosslinkable composition comprising two or more different curingmechanisms, said RMA crosslinkable composition comprising at least onecrosslinkable component comprising one or more reactive components A andB each comprising at least 2 reactive groups wherein the at least 2reactive groups of component A are acidic protons C—H in activatedmethylene or methine groups, and the at least 2 reactive groups ofcomponent B are activated unsaturated groups C═C which reactive groupsreact to achieve crosslinking by Real Michael Addition reaction in thepresence of a base catalyst C, said method comprising the steps of: a.providing the RMA crosslinkable composition; b. applying a layer of saidRMA crosslinkable composition to a substrate; c. allowing curing of thelayer by RMA crosslinking by reacting the acidic protons (C—H) inactivated methylene or methine groups with the activated unsaturatedgroups (C═C) by RMA crosslinking in the presence of the base catalyst(C); d. after said applying and before, during, or after said RMAcrosslinking performing a second crosslinking reaction step; wherein thetwo or more different curing mechanisms comprise: a. RMA crosslinking incombination with a second crosslinking reaction between hydroxy groupson the RMA crosslinkable components with polyisocyanates or siloxanes;or b. RMA crosslinking in combination with a second crosslinkingreaction with polyamines, with crosslinkable components comprisingcomponent B and/or with epoxy groups on the RMA crosslinkablecomponents; or c. RMA crosslinking in combination with a secondcrosslinking reaction based on auto-oxidative drying of unsaturatedgroups on the RMA crosslinkable components; or d. RMA crosslinking incombination with a second radical crosslinking reaction of reactivecomponents B on the RMA crosslinkable components; or e. combinationsthereof.
 2. The method of claim 1, wherein the RMA crosslinkablecomposition comprises an RMA crosslinkable resin containing one or morefatty components selected from the group of fatty acids, fatty alcohols,fatty amines, fatty thiols, and at least 2 reactive groups which areacidic protons C—H in activated methylene or methine groups wherein theactivated C—H reactive groups are in one or more reactive components Ahaving a structure according to formula 1:

wherein R is hydrogen or an alkyl or aryl and Y and Y′ are identical ordifferent substituent groups, or wherein the —C(═O)—Y and/or —C(═O)—Y′is replaced by CN or aryl.
 3. The method according to claim 2, whereinthe fatty compounds in the RMA crosslinkable resin are selected from thegroup consisting of fatty compounds having unsaturated groups, epoxygroups, hydroxy groups, and combinations thereof.
 4. The methodaccording to claim 3, wherein the fatty compounds are fatty acidscomprising C8 to C18 chain with 20, 25, 30 or 40 to 99 wt% of the fattyacids being unsaturated fatty acids for auto-oxidative crosslinking. 5.The method according to claim 3, wherein the fatty compounds are fattyacids comprising a C8 to C18 chain with hydroxyl groups and/or compriseother hydroxyl groups on the crosslinkable components and the RMAcrosslinkable composition further comprises polyisocyanates or siloxanesfor crosslinking with the hydroxyl groups.
 6. The method according toclaim 3, wherein the fatty compounds are fatty acids comprising a C8 toC18 chain with epoxy groups and the RMA crosslinkable compositionfurther comprises polyamines.
 7. The method according to claim 3,wherein the RMA crosslinkable composition comprises a thermal orradiation radical initiator for thermal or radiation radicalcrosslinking.
 8. The method according to claim 7, wherein the RMAcrosslinkable composition comprises an excess of the one or morereactive components B over the one or more reactive components A in theRMA crosslinkable composition, wherein the RMA crosslinkable compositioncomprises more than 60 wt% radical curable components, less than 40 wt%of RMA crosslinkable components comprising component A, the sum thereofbeing 100 wt%, and a radical initiator and, wherein crosslinking is doneafter an initial RMA curing to increase the viscosity of the coatinglayer before UV curing.
 9. The method according to claim 7, wherein theRMA crosslinkable composition comprise acrylate as well as methacrylateacceptors as the one or more reactive components B.
 10. The method ofclaim 1, wherein the one or more reactive components A are predominantlymalonate, predominantly meaning that more than 50% of the C—H reactivegroups in the reactive components A are from malonate.